1. Field of the Invention
The invention generally relates to environmental seals for closing openings for pressure chambers, and more particularly to an environmental seal for sealing the opening of an exit cone for a rocket nozzle.
2. Description of the Prior Art
The prior art is, of course, replete with rocket nozzle closure members adapted to function as environmental seals. For example, see United States Letters Patents to George K. Oss No. 3,229,635 and 3,228,334. Each of these patents discloses a seal for a rocket motor. The patented seals are adapted to be expelled in response to a build-up of pressure within the nozzle.
In many solid rocket motor applications it is required that the nozzles of the motors be environmentally sealed until ignition occurs. Usually, the environmental seal is blown off at or immediately prior to ignition. Unfortunately, however, in some cases this technique simply is not acceptable since the resultant ejecta tends to be hazardous to nearby hardware. This is particularly true for space shuttle booster separation motors. Moreover, as pointed out by the patentee Oss, aforementioned, it also is desirable to assure that seals be removed in a manner which leaves the nozzle free and clear of ejecta in order to avoid interference with missile guidance.
It is, therefore, the general purpose of the instant invention to provide a retractable environmental seal for sealing the opening of an exit cone for a rocket nozzle which leaves no ejecta upon removal, ensures that adjacent hardware is protected and/or assures that guidance interference is avoided.